This invention relates to loose fill heat insulation for building structures, particularly to the type of loose fill insulation that is blown into attics, walls, and other large spaces.
When loose fill insulation is installed in a building structure, usually by being carried by an air stream through a flexible conduit and blown into place, it is important that the insulation have a low settled density, in that it does not become packed or compressed after having been installed. The low settled density enables the loose fill insulation to maintain a high R value or high thermal resistance, less weight of the insulation is required to fill the spaces being insulated, and less time is required for the workers to fill the space with the material. Other attendant advantages include the requirement of less fire retardant chemicals per pound of the insulation, and less weight to be supported by the building structure. One of the most significant improvements is that a low settled density of loose fill insulation improves the smoldering characteristics of the insulation, in that the potential for insulation smoldering is significantly reduced. These and other characteristics, such as corrosion characteristics, are set forth for acceptable loose fill insulations by U.S. Government General Services Administration Standard HH-I-515D dated June 15, 1978, by Consumer Product Safety Commission Safety Standard, 16 CFR, Part 1209, and by A.S.T.M. C739.
The conventional loose fill cellulose insulation is cellulose treated with a fire retardant. The cellulose can comprise virtually any cellulosic material that can flow in an air stream, and preferably the cellulose should be of low density. The cellulose is treated with a fire retardant such as a mixture of equal parts of boric acid and borax 5 mol, by coating the cellulose with the fire retardant.
It has been found that when the settled density of loose fill cellulosic insulation is reduced, less fire retardant per pound of insulation is required to achieve low smoldering characteristics.